Immune dysregulation can be a component of many pathological diseases or conditions. Such dysregulation may be a factor that favors the establishment, maintenance or progression of these diseases or conditions. Deficient immune responses or immune suppression can enhance a mammal's susceptibility to infection or to the development of cancer. Conversely, excessive or inappropriate immune responses can play a role in the establishment or progression of unwanted inflammation or autoimmune conditions. It would thus be advantageous to utilize agents that can modulate immune responses and to at least partially reverse immune dysregulation when such dysregulation is a component of a given pathological condition. Some agents are known that can ameliorate some aspects of immune dysregulation, but typically such agents have their own unwanted effects on either the host's immune system or other organs or tissues. Agents such as glucocorticoid steroids have been used to reduce unwanted inflammation in a number of clinical conditions, but such compounds often have serious limitations, such as inducing immune suppression or causing unwanted mood changes.
Human and mammalian immune responses to infections or other conditions are often characterized by responses mediated by different immune effector cell populations. In some situations, helper T cells designated Th1 in the murine system, facilitate immune effector functions that are typically dominated by cell-mediated responses. In other cases, helper T cells designated Th2 cells facilitate immune effector functions that are typically dominated by humoral responses. A vigorous Th1 response is usually desirable to help clear infections or to slow the progression of an infection. When a subject's immune response is biased to, or dominated by, a Th2-type response, the cytokines associated with the Th2 response tend to suppress the immune system's capacity to mount a vigorous Th1 response at the same time. The converse is also generally true. When mammalian immune responses begin to result in an increasing Th1 response, Th2 responses tend to weaken. Insufficient Th1 responses may be associated with progression of some infections or other conditions, see, e.g., M. Clerici and G. M. Shearer, Immunol. Today 14:107-111, 1993; M. Clerici and G. M. Shearer, Immunol. Today 15:575-581, 1994.
There is a current need for cost-effective pharmaceutical agents and treatment methods for treating various immune dysregulation conditions. The invention provides compounds that can be used in such treatments to treat or ameliorate one or more aspects of immune dysregulation conditions. Such agents can be used to treat autoimmune or inflammation conditions, immune suppression conditions, infections, blood cell deficiencies and other described conditions. The agents and methods are useful to ameliorate these conditions or one or more symptoms associated with any of these conditions. The use of these agents can be combined with one or more conventional treatments for these disorders.